How to wipe a dead hard drive?

October 29, 2007 10:28 AM

How to wipe a dead hard drive? After backing up my data to a recently purchased external drive, it promptly failed (and produced a horrible, burning electronics odor). As I'm still within the 14 day return policy, I shouldn't have any trouble returning it. However: I want to wipe all of my personal data from the drive first. How to do that with a drive that won't mount?

I've a feeling the problem lies not in the drive itself, but in the power supply or something similar. So I suppose I could remove the drive itself and write it with zeroes. But this would, mostly likely, void my warranty. Is there something similar to an old tape degausser that will work with drives?

I'm not going for NSA level formatting here, but I'd like to minimize the possibility that the drive gets restocked with all of my data (a full disc image of my machine) still on it. Ideas?

posted by aladfar to computers & internet (16 comments total)

You should talk to the vendor or manufacturer (whomever is covering the warranty) to see their policy on this. Any method you use to ensure your data is not accessed in the future would involve either disassembling the external enclosure or even destroying the drive itself (perhaps by drilling through it).

Either of these approaches would likely result in the warranty being revoked. Consult with the warranty provider ASAP.
posted by BigLankyBastard at 10:40 AM on October 29, 2007

Rare earth magnet.
posted by caddis at 10:48 AM on October 29, 2007

Iron nail, copper wire, electric current (9 volt battery).

Wrap the copper wire around the iron nail, connect the ends of the copper wire to the positive and negative leads of the battery. Instant electro-magnetic field. Touch to hard drive. Data corruption is achieved.

If you really want to get silly, use a lantern battery (12 volt). Also remember, the more turns of the copper around the nail, the stronger the electromagnetic field strength.

And yes, a tape degausser is just a fancy electromagnet.
posted by daq at 10:53 AM on October 29, 2007 [1 favorite has favorites]

Seconding a strong magnet as being a non-destructive method of erasing it.
posted by chrisamiller at 11:00 AM on October 29, 2007

Thirding the magnet.
posted by LunaticFringe at 11:12 AM on October 29, 2007

I have some concerns about the magnet idea... those hard drive enclosures are somewhat shielded.
posted by zek at 11:43 AM on October 29, 2007

Using a magnet on it is "non-destructive" in that it doesn't leave physical evidence that can be easily noted at first glance. I would be very surprised if you could get warranty service on a drive you'd wiped with a magnet, though. BigLankyBastard has it--this is a matter of the drive company's privacy policy. If the drive isn't powering up, you can't wipe it in a way that won't void your warranty.
posted by hades at 11:43 AM on October 29, 2007

A rare earth magnet probably isn't going to do it.

The drive head is floating microns above the surface of the platter and has a tremendous amount of magnetic power concentrated over a very small area (think "magnetic black hole"). A rare earth magnet, even a very strong one, that isn't also microns from the surface of the platter, is going to have a far smaller effect (think "lunar tides"). Sure, the tides move the ocean around, but they don't tip over dominoes -- and the data (magnetic domains) written on your hard drive are just like little dominoes.

You need alternating current (like the drive head uses), not direct current (like a battery provides), to really make a change, and you need a massive magnetic field very, very close to the media surface. A tape degausser might do it, but I wouldn't even bank on that. An MRI machine might do it, but it would shred the drive enclosure first.

Hard drives are tough. When businesses want to be sure they're unreadable, they throw them in a shredder. Nothing else is guaranteed, except possibly incineration -- but you're going to need enough heat that it will melt everything else on the drive first -- and blow your warranty.

I don't suppose "don't worry about it" is on your list of options? How about "just throw the drive away, it's cheap insurance."
posted by seanmpuckett at 11:43 AM on October 29, 2007

A magnet should work but there is no way to verify that it did without a working drive. If you are really worried take a hammer to it and get a new one, warranty be damned.
posted by chairface at 11:45 AM on October 29, 2007

On closer reading, it sounds like maybe the enclosure is bad, not the drive. If that's the case, and opening the enclosure to take the drive out voids your warranty, then you're just as screwed. Otherwise, like you said. Take the drive out, wipe it in another enclosure (I like DBAN), put the drive back in the dead enclosure and send the whole thing back.
posted by hades at 11:46 AM on October 29, 2007

Try a magnetic tape bulk eraser, something strong enough to do DLT tapes. Zap the drive with that for 30+ seconds.

Other than a power drill, that's the only way I can think to make a hard drive unusable that you can't mount.
posted by mrbill at 12:25 PM on October 29, 2007

The nail/battery/magnet thing will not work. First, I doubt that the field it produces is strong enough to degauss a hard drive platter. Second, even if it is, a unchanging magnetic field won't necessarily wipe media -- to really erase, you need a fluctuating field, and then you need to slowly diminish its intensity, so you leave infinitesimally-thin 'layers' in the media in opposite directions. And third, the hard drive is in a metal box; a nail and a 9V aren't going to penetrate that very well.

If you really wanted to MacGuyver this, it would probably work to wrap the drive itself in a few hundred turns of wire, and then connect that to an autotransformer, plugged into AC power, and start it up at some high voltage and then run the voltage slowly down to zero. That would probably be enough to ensure saturation, and then complete elimination of data as you diminish the field and randomize the platters from inside to out.

But really, there's a reason why people dealing with sensitive data in the real world don't do this; it's hard to prove that you really destroyed the data without destroying the drive. And this is why the real DOD standards for media that have had classified stuff on them isn't overwriting, it's incineration.

Moral of the story: if you care about data security, buy OEM drives (from a good brand, but no warranty, since you can't use it) and when they fail, take them apart with a Torx driver, break or bake the platters, and throw them away.
posted by Kadin2048 at 12:40 PM on October 29, 2007

The ACCRC in Berkeley charges $10 to wipe a drive with their giant degausser.
posted by Zed_Lopez at 1:07 PM on October 29, 2007 [1 favorite has favorites]

Thanks for the advice all. I'm reluctant to simply eat the cost of the hard drive as I just purchased it and it was fairly expensive for me.

If I can easily pull the drive out of the case I'll try to zero it out with another enclosure. Otherwise, I'll simply have to take my chances with Lacie's privacy policy.

Then again, as it has all of my email, tax records and personal media perhaps taking a loss of a couple hundred bucks is worth it.
posted by aladfar at 1:12 PM on October 29, 2007

Sounds like the lesson to learn here is to store your sensitive files in an encrypted format.
posted by philomathoholic at 1:40 PM on October 29, 2007 [2 favorites has favorites]

I thought I'd follow up to my own question for posterity. I had a good conversation with the someone at LaCie tech support and was told that they format all incoming drives as a matter of course.

When I mentioned my concern about having my data restocked on a shelf somewhere, he said policies were in place to prevent that situation from happening. So while I remain a bit wary, I think I'll be OK in returning it to the Apple store.
posted by aladfar at 8:49 AM on October 31, 2007